First I should note that I assume GNOME or KDE probably does a great job automounting the Canon PowerShot A590, or at least getting the pictures off of it. Not having GNOME or KDE, however, I'd like to do it from the command line.

Lots of cameras will automatically be recognized as USB mass-storage devices. If this is your camera, great. Just find the camera with "fdisk -l" (as root), and mount it. Then use it like any other mounted drive. Unfortunately, The PowerShot A590 does not work that way (I think it may use PTP - Photo Transfer Protocol). For these kinds of devices, "fdisk -l" yields nothing. You can, however, see that the system took note of the camera if you look at /var/log/messages